title: Surface functionalization of nanostructured Fe2O3 polymorphs: from design to light-activated applications.
abstract: Nanostructured iron(III) oxide deposits are grown by chemical vapor deposition (CVD) at 400-500 °C on Si(100) substrates from Fe(hfa)2TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N',N'-tetramethylethylenediamine), yielding the selective formation of α-Fe2O3 or the scarcely studied ε-Fe2O3 polymorphs under suitably optimized preparative conditions. By using Ti(OPr(i))4 (OPr(i) = iso-propoxy) and water as atomic layer deposition (ALD) precursors, we subsequently functionalized the obtained materials at moderate temperatures (<300 °C) by an ultrathin titanomagnetite (Fe3-xTixO4) overlayer. An extensive multitechnique characterization, aimed at elucidating the system structure, morphology, composition and optical properties, evidenced that the photoactivated hydrophilic and photocatalytic behavior of the synthesized materials is dependent both on iron oxide phase composition and ALD surface modification. The proposed CVD/ALD hybrid synthetic approach candidates itself as a powerful tool for a variety of applications where semiconductor-based nanoarchitectures can benefit from the coupling with an ad hoc surface layer.
authors.affiliation: IENI-CNR and INSTM, Department of Chemistry, Padova University, Via Marzolo 1, 35131 Padova, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Barreca
authors.forename: Giorgio
authors.initials: G
authors.lastname: Carraro
authors.forename: Alberto
authors.initials: A
authors.lastname: Gasparotto
authors.forename: Chiara
authors.initials: C
authors.lastname: Maccato
authors.forename: Francesca
authors.initials: F
authors.lastname: Rossi
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Salviati
authors.forename: Massimo
authors.initials: M
authors.lastname: Tallarida
authors.forename: Chittaranjan
authors.initials: C
authors.lastname: Das
authors.forename: Fernando
authors.initials: F
authors.lastname: Fresno
authors.forename: Dorota
authors.initials: D
authors.lastname: Korte
authors.forename: Urška Lavrenčič
authors.initials: UL
authors.lastname: Stangar
authors.forename: Mladen
authors.initials: M
authors.lastname: Franko
authors.forename: Dieter
authors.initials: D
authors.lastname: Schmeisser